Aircraft engines, generally gas turbines, are periodically cleaned to remove dirt and grime from internal components of the engine. To clean the engines, water or another cleaning agent is introduced into the engine and the engine is dry motored (rotated without burning fuel) to draw the water over the internal components to be cleaned.
Sometimes, before introducing water into the engine, maintenance crews must take steps to disconnect the engines from other aircraft systems to prevent dirty water moving through the engines from escaping into the other aircraft systems. For example, crews may disconnect air supply systems, fuel manifold systems, anti-ice systems, pressure regulation systems, and/or controller systems before introducing water into the engine. These steps may take an inconvenient amount of time and may be difficult to perform.
Additionally, dry motoring of aircraft engines being cleaned is often driven by an engine starter included in the aircraft. These engine starters are generally limited to constant operation for only a few minutes before they have to be rested to avoid overheating or other damage. Accordingly, cleaning cycles that call for extended periods of dry motoring may take in inconvenient amount of time while the engine starters are rested between uses. The additional time required to cool these systems as well as the maintenance requirements for cleaning can sometimes lead to aircraft operators to defer or to cancel engine cleaning operations.